Fig. 3.

Correlation in RTL measured in samples collected from the same individual wandering albatrosses and zebra finches, but stored in different ways. For the albatross study a, samples were collected 12–14 years apart, with the first sample stored either as extracted DNA or as frozen red blood cells (n = 30), and the second sample stored on FTA cards. For the zebra finch study b, a single sample was collected from each individual (n = 30), and this was split and stored in different ways for 2 months. Points show raw data. There was a significant correlation between RTL measures in zebra finch samples which were stored as extracted DNA and those that were frozen as whole blood (r = 0.593, p < 0.001), but none of the other correlations were significant (see Results)